Geological Survey of Denmark and Greenland Bulletin 3, 1-23 1 GEOLOGICAL SURVEY OF DENMARK AND GREENLAND BULLETIN 3 · 2004 Late Quaternary environmental changes recorded in the Danish marine molluscan faunas Kaj Strand Petersen GEOLOGICAL SURVEY OF DENMARK AND GREENLAND MINISTRY OF THE ENVIRONMENT GEUS Bulletin no 3.pmd 28-06-2004, 08:451 2 Geological Survey of Denmark and Greenland Bulletin 3 Keywords Bottom-communities, climate changes, Danish, environment, interglacial–glacial cycle, Late Quaternary, marine, mollusc faunas. Cover Donax vittatus on the sandy shores of northern France. Kaj Strand Peteresen Danmarks og Grønlands Geologiske Undersøgelse Øster Voldgade 10, DK-1350 Copenhagen K, Denmark E-mail: ksp@geus.dk Scientific editor of this volume: Svend Stouge Editorial secretaries: Esben W. Glendal and Birgit Eriksen Referees: Svend Funder and Gotfred Høpner Petersen, Denmark Illustrations: Gurli E. Hansen Bengaard and Henrik Klinge Pedersen Digital photographic work: Benny M. Schark and Jakob Lautrup Graphic production: Knud Gr@phic Consult, Odense, Denmark Printers: Schultz Grafisk, Albertslund, Denmark Manuscript submitted: 9 January 1998 Final version approved: 11 December 2003 Printed: 15 July 2004 ISBN 87-7871-122-1 Geological Survey of Denmark and Greenland Bulletin The series Geological Survey of Denmark and Greenland Bulletin replaces Geology of Denmark Survey Bulletin and Geology of Greenland Survey Bulletin. Citation of the name of this series It is recommended that the name of this series is cited in full, viz. Geological Survey of Denmark and Greenland Bulletin. If abbreviation of this volume is necessary, the following form is suggested: Geol. Surv. Den. Green. Bull. 3, 268 pp. Available from Geological Survey of Denmark and Greenland Øster Voldgade 10, DK-1350 Copenhagen K, Denmark Phone: +45 38 14 20 00, fax: +45 38 14 20 50, e-mail: geus@geus.dk or Geografforlaget ApS Rugårdsvej 55, DK-5000 Odense C, Denmark Phone: +45 63 44 16 83, fax: +45 63 44 16 97, e-mail: go@geografforlaget.dk © Danmarks og Grønlands Geologiske Undersøgelse (GEUS), 2004 GEUS Bulletin no 3.pmd 28-06-2004, 08:452 3 Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Danish sites with marine sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 The Late Pleistocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 The Holocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 The recent fauna of shell-bearing molluscs compared to the subfossil fauna . . . . . . . . . . . 12 Molluscan finds within the seven regions during the Holocene . . . . . . . . . . . . . . . . . . . . . 15 The Bælt Sea area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 The Baltic area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 The Kattegat area with fjords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 The Limfjord area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 The North Sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 The Vendsyssel area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 The Skagen Well area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 The Danish Late Quaternary marine molluscs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Class Polyplacophora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Order Neoloricata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Class Gastropoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Subclass Prosobranchia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Order Archaeogastropoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Order Mesogastropoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Order Heterogastropoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Order Neogastropoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Subclass Heterobranchia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Order Heterostropha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Subclass Opisthobranchia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Order Bullomorpha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Order Anaspidea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Order Thecosomata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Order Gymnosomata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Subclass Pulmonata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Order Basommatophora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Class Scaphopoda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Order Siphonodentalioida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Order Dentalioida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Class Bivalvia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Subclass Palaeotaxodonta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Order Nuculoida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Subclass Pteriomorphia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Order Arcoida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Order Mytiloida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Order Pteroida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Subclass Heterodonta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Order Veneroida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Order Myoida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Subclass Anomalodesmata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Order Pholadomyoida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 GEUS Bulletin no 3.pmd 28-06-2004, 08:453 4 The Skagen Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 The Skagen Well – perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 The pre-Late Quaternary deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 The Late Pleistocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Eemian deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 The Early/Middle Weichselian, marine and glacigene deposits . . . . . . . . . . . . . . . . . . 100 The Late Weichselian marine and glacigene deposits . . . . . . . . . . . . . . . . . . . . . . . . . 101 The Holocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 The Preboreal–Boreal 10 000 – 8000 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . 103 The Atlantic 8000–5000 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 The Subboreal 5000–2500 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 The Subatlantic 2500– 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 The older Subatlantic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 The younger Subatlantic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Conclusive remarks on the Skagen Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 The environmental changes through time in the seven sectors based on the molluscan records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Eemian species sorted after climatic affinities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 The Bælt Sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 The Baltic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 The Kattegat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 The North Sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 Vendsyssel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 Skagen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Early/Middle Weichselian species sorted after climatic affinities . . . . . . . . . . . . . . . . . . . . 126 The Kattegat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Vendsyssel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 Skagen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Late Weichselian species sorted after climatic affinities . . . . . . . . . . . . . . . . . . . . . . . . . 130 Vendsyssel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Skagen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Holocene species sorted after climatic affinities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 The Bælt Sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 The Baltic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 The Kattegat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 The Limfjord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 The North Sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Vendsyssel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Skagen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 The environmental changes within the seven regions through the Late Quaternary evaluated by the molluscan communities met with in the seven stages . . . . . . . . . . . . 151 Eemian stage 130 000 – 115 000 B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 The Bælt Sea, region 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 The Baltic, region 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 The Kattegat, region 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 The North Sea, region 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 The Vendsyssel region, region 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 The Skagen region, region 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 Early/Middle Weichselian stage 115 000 – 25 000 B.P. . . . . . . . . . . . . . . . . . . . . . . . . . 157 The Kattegat, region 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 The Vendsyssel region, region 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 GEUS Bulletin no 3.pmd 28-06-2004, 08:454 5 The Skagen region, region 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Late Weichselian stage 25 000 – 10 000 B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 The Vendsyssel region, region 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 The Skagen region, region 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 The Preboreal–Boreal stage 10 000 – 8000 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . 159 The North Sea, region 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 The Skagen region, region 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 The Atlantic stage 8000–5000 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 The Bælt Sea, region 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 The Baltic, region 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 The Kattegat, region 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 The Limfjord, region 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 The North Sea, region 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 The Vendsyssel region, region 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 The Skagen region, region 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 The Subboreal stage 5000–2500 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 The Bælt Sea, region 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 The Baltic, region 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 The Kattegat, region 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 The Limfjord, region 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 The North Sea, region 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 The Vendsyssel region, region 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 The Skagen region, region 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 The Subatlantic stage 2500– 14C years B.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 The Bælt Sea, region 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 The Baltic, region 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 The Kattegat, region 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 The Limfjord, region 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 The North Sea, region 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 The Vendsyssel region, region 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 The Skagen region, region 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Concluding remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 List of synonyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 Index of species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 Appendix 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 Recent species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 Subfossil species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 Recent species sorted after climatic affinities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 Subfossil species sorted after climatic affinities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Appendix 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Appendix 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 Appendix 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258 Appendix 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 Appendix 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 GEUS Bulletin no 3.pmd 28-06-2004, 08:455 6 GEUS Bulletin no 3.pmd 28-06-2004, 08:456 7 Abstract Petersen, K.S. 2004: Late Quaternary environmental changes recorded in the Danish marine molluscan faunas. Geological Survey of Denmark and Greenland Bulletin 3, 268 pp. Late Quaternary, marine deposits in Denmark have yielded 247 subfossil species of molluscs. The sites are presented, and comparisons are made between the subfossil mollusc assemblages and the 278 shell-bearing mollusc species presently living in the Danish seas. 184 species are common to the two groups. The 63 species no longer occurring around Denmark are used as indicators of changing environmental conditions, including temperature, salinity and depth, throughout the last 130 000 years. Seven modern faunal regional units are defined and consid- ered: the Bælt, the Baltic, the Kattegat, the Limfjord, the North Sea and the Vendsyssel regions, and the Skagen area based on the Skagen III Well DGU File No. 1.287. The Late Quaternary, marine, shell-bearing molluscs, comprising 341 subfossil and recent species, are characterised from the point of view of climatic (i.e. Arctic, Subarctic, Boreal and Lusitanian) affinities and animal–sediment relationships. On this background the faunal and environmental evolution recorded in the 217 m long Skagen Well core is analysed and described. The mollusc assem- blages in the Skagen sequence indicate a deeper-water facies during the Eemian, the Weichse- lian and the older Holocene in contrast to what hitherto was known in other parts of the Danish area during the Late Quaternary. For the Skagen Well the chronozones Preboreal/Boreal, Atlan- tic, Subboreal and Subatlantic can be identified by 14C dating. The environmental changes within the seven regions through the Late Quaternary are evaluated by depicting the molluscan communities encountered in the seven Late Quaternary stages together with remarks on studies of the neighbouring areas. By following the marine communities through the Late Quaternary in the light of the classical bottom communities sensu C.G.J. Petersen, it is demonstrated how facies have changed both through time and space within the Danish marine realm. The well- established, more temperate Eemian marine fauna was closely associated with shallow-water environments. The inferred climatic changes reflect an interglacial–glacial cycle. However, the climatically induced changes during the Holocene in the marine environment were small and overshadowed by the facies changes. Out of the 341 species recorded in this study, 140 occur in the Eemian, 36 in the Early/Middle Weichselian and 41 in the Late Weichselian. The Holo- cene fauna is represented by 183 species of shell-bearing molluscs, of which the first recorded occurrence of 148 species has been radiocarbon-dated. Author’s address Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: ksp@geus.dk GEUS Bulletin no 3.pmd 28-06-2004, 08:457 8 50 km Korsør Holbæk Høng Blåvands Huk Mandø Hølade Frederikshavn Korupsø Agger Tange Agger Bovbjerg Ertebølle Tastum Sø Gedser Darss Stavtrup Hals Hollerup Ejby Bro Limhamn Aarhus Stensigmose Voderup Klint Ristinge Strandegaard Dyrehave Hobro Aalbæk Jydske Rev Saltholm Læsø Anholt Skagen Amager Djursland Vendsyssel Dybvad Skærumhede Ærø Jerup Vester Holmen Samsø Højen Vust Kovad Bro Vognsbøl Fredericia Esbjerg Varde Forballum Grærup Farup Tønder Yder Bjerrum Røjle Klint Holmstrup Røsnæs Ulfborg Bulbjerg Løkken Strandby Bindslev Bornholm Møn Rügen Vejle Fjord Mariager Fjord Tybrind Vig Sidinge Fjord Skive Fjord Nissum Fjord Isefjord Roskilde Fjord Limfjorden Fakse Bugt Skagerrak Lille Bæ lt Store Bæ lt Ø resund København Jylland Sjælland Fyn NORTH SEA BALTIC SEA Bælt Sea Kattegat 57° 55° 8° 10° 12° 14° Fig. 1. Location map with Late Quaternary marine localities and names of areas on land and of Danish waters. GEUS Bulletin no 3.pmd 28-06-2004, 08:458 9 Introduction In the middle of 19th century, Denmark had its first ‘Geology of Denmark’ published by G. Forchhammer, in 1835. However, as Forchhammer expressed it in 1851 when making some notes on the work by the malac- ologist O.A.L. Mørch (1828–1878) at the Mineralogical Museum of Copenhagen. It has hitherto been enough for the geognost to establish formations using the char- acteristic fossils, but in the future we have to give a closer description from a zoological point of view (Pe- tersen 1997, p. 5). Considering only the younger de- posits, the efforts of the zoologist in geological works are highly significant and became important already in the 19th century. C.G.J. Petersen (1860–1928) is an out- standing example of such an influence with his work on the extent of shell-bearing molluscs in the Danish seas inside the Skagen (Petersen 1888, 1893). Here he points to the faunal conditions also in the Pleistocene and Holocene marine deposits compared to the recent distribution. In the description accompanying the geo- logical map sheets of Vendsyssel (Jessen 1899), Jessen gives full credit to C.G.J. Petersen and A. Jensen (1866– 1953) for their studies on the molluscan species re- corded from that part of the country. Later both Peter- sen and Jensen contributed further to our knowledge of the marine molluscan fauna. Petersen formed the concept of the bottom communities (Petersen & Jen- sen 1911; Petersen 1913, 1914, 1915, 1918) that has been the tool for further work, not only within the Danish waters but all over the world with the so-called parallel bottom communities (Thorson 1957). Though the concept of parallel molluscan communities in the sense of Thorson (1957) has been considerably modi- fied in the last 30 years (Erwin 1983), there remains a recognition that particular molluscan assemblages are associated with various types of habitat. In 1899 the zoologist V. Nordmann (1872–1962) was engaged by the Geological Survey of Denmark to study the mol- luscs from the Quaternary deposits. Part of this work was already reflected in the next geological map sheet covering the southern part of Vendsyssel (Jessen 1905). Here Nordmann has identified the molluscs and given the faunal remarks on the Holocene marine fauna in the north-eastern part of the Limfjord (Fig. 1). In his work, the zoological considerations are given, eluci- dating the Holocene palaeoenvironments. However, from the beginning of the century Nordmann touched upon many other aspects within the Late Quaternary marine environments which form the most important base for the present study covering marine deposits from the Eemian, the Weichselian and the Holocene. In the following chapter the presentation of some observed sites with marine sediments will be given as an introduction to an answer to the question raised by Petersen (1910, p. 29): “What I have often missed in the geological studies is a thorough or detailed com- parison between the fossil faunas and the molluscan faunas now living before our eyes”. The aim of this work is to characterise the changing environments in the Danish waters through time as seen in the macrofaunas and bottom communities mainly based on molluscs. Danish sites with marine sediments Initially, the findings and descriptions of the Danish marine localities shown in Fig. 1 were part of the uni- versity studies pioneered by G. Forchhammer. How- ever, since the start of the Geological Survey of Den- mark in 1888, much of the information has come from the systematic mapping of Denmark, and the results have been published in the descriptions to the geo- logical map sheets of Denmark (Fig. 2). As seen from the plan for the geological mapping of Denmark (e.g. Sørensen & Nielsen 1978) it was de- cided to do the mapping first in the northern parts of Jylland and Sjælland and to present a record of the marine deposits from the areas mapped. Today, up to 80 per cent of the country has been mapped and de- scriptions for many map sheets have been published. The main information on the Holocene marine mol- GEUS Bulletin no 3.pmd 28-06-2004, 08:459 10 luscs is available in these publications and is used in the present description supplemented by specific mol- luscan studies within the areas. Consequently, the frame will be the transition area between the North Sea and the Baltic and the descrip- 57° 55° 8° 10° 12° 14° 50 km 1. Bælt Sea 2. Baltic Sea 3. Kattegat Vend- syssel 7. Skagen N o r t h S e a 4. Lim- fjorden 5. 6. Region 1 – 7 Fig. 2. The frame for the seven regions follows mainly the pattern of the old geological map sheets (Sørensen & Nielsen 1978, fig. 1) and partly the regions used in Jensen & Knudsen (1995, fig. 1). 1: The Bælt Sea covering the southern part of the Bælts. 2: The Baltic covering the southern part of Øresund and east of Darss–Gedser. 3: The Kattegat region covering the northern part of the Bælts and Øresund. 4: The western Limfjord – except the North Sea coastal region. 5: The North Sea with coastal regions and Skagerrak. 6: Vendsyssel including former marine areas. 7: Skagen, mainly the Skagen Well DGU File No. 1.287. tion mainly based on the geological map sheets found in the following regions shown in Fig. 2: (1) The Bælt Sea; (2) The Baltic; (3) The Kattegat with bordering fjords; (4) The Limfjord; (5) The North Sea; (6) Vend- syssel and The Skagen Well III, DGU File No. 1, 287. The Late Pleistocene In 1841 Forchhammer found the Cyprina Clay to the southern part of Denmark, naming the unit after the dominating bivalve (Forchhammer 1842). First, how- ever, Forchhammer referred the thick shell molluscs to Glossus humanus rather than to Arctica islandica. Consequently, he placed the deposits in the ‘Brun- kulsformation’, viz. the Tertiary. When finally realising that the common species was Arctica islandica, he transferred the deposits to the so-called ‘Rullestensfor- mation’, viz. the Quaternary. Along with the investiga- tions of the Cyprina clay through the years since 1841, the actual stratigraphical position was very much un- der debate, and it was not until 1928 when Nordmann wrote his La Position stratigraphique des Dépôts d’Eem that the Cyprina clay attained its final position: “appartenant à la dernière période interglaciaire” (Nord- mann 1928, p. 65). Later the name ‘Eemian’ became the designation for the whole interglacial, according to Gripp (1964, pp. 215–216). Johnstrup (1882a) gave the first detailed description of the Cyprina Clay in Denmark and Slesvig. Also in the northern part of Denmark, Late Pleistocene deposits were studied by Johnstrup (1882b), but with references to the earlier works by Forchhammer (1822), Bredsdorff (1824), Faber (1828) and Pingel (1828). In 1908 Nordmann made his doctoral thesis on the molluscan fauna from the Cyprina Clay and other central European deposits, forming a part of the publication by Madsen et al. (1908). The sequence of interglacial–glacial marine depos- GEUS Bulletin no 3.pmd 28-06-2004, 08:4510 11 its is described from the well at Skærumhede (Jessen et al. 1910). Here the full Late Pleistocene record is found, although the stratigraphic position was not clear at that time. Later investigations, also with studies of the molluscan fauna, were published in 1974 and a Late Pleistocene age proposed (Bahnson et al. 1974). The difference between the Boreo-Lusitanian commu- nity in the boring and the typical Eemian community as found in southern Denmark was interpreted as dif- ference in facies (Bahnson et al. 1974) (see Nilsson 1983). In the study of the marine Late Pleistocene deposits in southern Denmark (Ødum 1933) based on the record of molluscan species as determined by V. Nordmann the finds point to two different deposits in time. One is regarded as Eemian and the other as the so-called Skærumhede fauna. However, later investigations at Strandegaards Dyrehave in southern Sjælland (Peter- sen & Konradi 1974) and at Holmstrup in central Sjælland (Fig. 1; Petersen & Buch 1974), revealed that the molluscan species found at Strandegaards Dyrehave, one of the localities of Ødum (1933) and regarded as representing the Skærumhede fauna, could be Eemian but reflecting another facies than the typical Eemian on the islands south of Fyn. The Holmstrup fauna is to be correlated with the Arctic marine Weichselian in northern Jylland which is the upper part of the Port- landia arctica zone sensu Nordmann (Madsen et al. 1908) or the Macoma calcarea zone sensu Petersen (Bahnson et al. 1974, fig. 7), see Fig. 3 for stratigraphi- cal position. The aminostratigraphic investigations of the Danish Late Pleistocene deposits as published by Miller & Mangerud (1985) sustain only to some extent the above- mentioned correlations: “None of the sites regarded here as Eemian (Strandegaards Dyrehave) gave ratios as high as in Holsteinian deposits or as low as in Mid- dle Weichselian deposits” (Miller & Mangerud 1985, p. 261). In the case of the Holmstrup Weichselian site, only three out of eleven individuals of Macoma calcarea gave Weichselian ratios (Miller & Mangerud 1985, p. 264). The marine molluscan fauna of the Late Weichse- lian has been studied intensively only from the Vend- H ol oc en e La te W ei ch se lia n Pl ei st oc en e M id dl e W ei ch se lia n Ea rl y W ei ch . Eemian L a t e Q u a t e r n a r y Subatlantic Subboreal Atlantic Boreal Preboreal Younger Dryas Allerød Older Dryas Bølling Historical age Iron age Bronze age Neolithic Mesolithic Palaeolithic Young Baltic Swedish Old Baltic Norwegian 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 15000 16000 17000 18000 19000 20000 21000 22000 1050 2050 2900 3700 4400 5500 6100 7200 8100 9100 10000 10200 11100 12100 12800 13400 14200 15100 16100 17000 17600 18500 25000 75000 115000 130000 Period Epoch Age Culture stageChron Ice stream chronology Calendar years BP 14C years BP Fig. 3. Stratigraphic framework for the Late Quaternary deposits from Pedersen & Petersen (1997). GEUS Bulletin no 3.pmd 28-06-2004, 08:4511 12 syssel area recorded in the publications by Jessen (1899, 1936). Nearly 30 molluscan samples from these Late Weichselian – Younger Yoldia Sea deposits have been dated (Krog & Tauber 1974). Theevaluationof themolluscancommunities inVend- syssel reveals the changing Late Weichselian sea level (Petersen 1984), and the highest marine shoreline, around 60 m a.s.l., in northern Denmark can be shown to develop between 14 000 and 13 000 B.P. (14C years). The Holocene Forchhammer participated in the work of the so-called ‘Lejrekomité’, an interdisciplinary committee studying human remains along the shore. This commission gave the first – and now famous – description of the ‘køk- kenmødding’ (kitchen midden), a mound consisting of shells of edible molluscs and other refuse, marking the site of a prehistoric human habitation (Hanks 1971). ‘Køkkenmødding’ is one of the few Danish interna- tional terms (Forchhammer et al. 1851). The work of the ‘Lejrekomité’ was concentrated on the marine mol- luscs in order to establish out whether the shell depos- its were naturally based – oyster banks – or whether they were formed as waste deposits produced by men living at coastal sites. The other members of the commission were J. Worsaae and J. Steenstrup, representing archaeology and zoology respectively. Consistently, the study of the molluscan elements was based mainly on Steen- strup’s work. However, while working in the commis- sion, Forchhammer continued his studies on the sea levels (Forchhammer 1838, 1840). This was essential for the discussion of whether the molluscs found be- longed to raised marine deposits or were gathered by man. Forchhammer’s study led to the concept of raised marine deposits north of a line from Nissum Fjord to south of Korsør in the Storebælt area (Fig. 1). This line still carries the name of Forchhammer and divides the country into two parts, with the raised marine areas to the north-east, and to the south-west the area where the land has been sinking. Together with the study of the Holocene molluscan fauna by Johnstrup (1882b), such observations on shorelines were also collected. It became one of the points specially mentioned in the instructions for the autographic geologists when the systematic geological mapping of Denmark was started in 1888 by the Geological Survey of Denmark (Sørensen & Nielsen 1978). The recent fauna of shell-bearing molluscs compared to the subfossil fauna The record of recent Danish shell-bearing molluscs has been taken from the annotated check list of recent marine molluscs of Danish waters (Jensen & Knudsen 1995). In Appendix 1 the species are presented taxonomically following Jensen & Knudsen (1995). Late immigrants from the last centuries – transferred by man -– have been omitted from the list, because the aim of the present study is to present the development in the subfossil Late Quaternary molluscan fauna also in Ap- pendix 1 compared to the natural fauna of today. Ac- cording to Fredén (1986), subfossil means that the weight of the object when found does not exceed its original weight, which is obviously the case for younger deposits seen geologically as shells from the Late Qua- ternary. In all, 278 recent species of shell-bearing molluscs are recorded from the Danish waters: The Class Polyplacophora is represented by seven GEUS Bulletin no 3.pmd 28-06-2004, 08:4512 13 species forming 2.5% of the total number of known species. The Class Gastropoda is represented by 151 species forming 54.3% of the total number of known species. The Class Scaphopoda is represented by three spe- cies forming 1.1% of the total number of known spe- cies. The Class Bivalvia is represented by 117 species forming 42.1% of the total number of known species. The list of known finds of subfossil species amounts to 247 species. With regard to the classes, it appears that Polyplacophora is now represented by only one species, which formed 0.4% of the total subfossil mol- luscan species. Within the Class Gastropoda 125 species occur, form- ing 50.6% of the total number of subfossil species, a figure which is nearly 5% lower than that for recent gastropods. The Class Scaphopoda is represented by five fossil species which form 2.0% of the subfossil shell-bearing species which is a little higher than the ratio for the recent fauna. The Class Bivalvia is represented by 116 species forming 47.0% of the total, which is a little more than 7% above the recent ratio. The low number of subfossil Polyplacophora can be explained by the fact that the shells from those species are nearly always broken, and this excludes identification to species level, so to say, following the statement made by Knudsen (1970, p. 1): “Isolated and worn plates were neglected altogether”. Among the Gastropods, the subclasses and orders, except the Order Heterostropha within the subclass Heterobranchia, have a lower representation of sub- fossil finds than of recent ones. The Heterostropha, which has a 2.5% higher representation among the subfossil finds than among the recent ones, is a group Fig. 4. Regional division of the Euro- pean seas from Feyling-Hanssen (1955). GEUS Bulletin no 3.pmd 28-06-2004, 08:4513 14 of mostly tiny specimens which might be more looked for in the geological samples than in the recent bot- tom samples often used in the more practical work of evaluation benthos introduced by C.G.J.Petersen. How- ever, many of these small species should be consid- ered with the utmost care, with respect to the diffi- culty of identifying them to species level within sub- fossil material. The reason why the Class Scaphopoda has a twice as great a representation within the subfossil material cannot be given, although it is tempting to regard the different palaeoenvironment back in the Late Quater- nary as the explanation of the higher frequency. The greater variety of palaeoenvironment and different cli- mate back in time is clearly the reason why the Bivalvia within all subclasses has a higher percentage than in the recent fauna. However, as an overview, the total subfossil species could be compared to the recent ones arranged also after their climatic affinities, as will be thoroughly dis- cussed in one of the following chapters. With respect to distribution of molluscan species within the North Atlantic – West European realm, four zones may be distinguished, viz.: the Arctic = a, the Subarctic = s, the Boreal = b and the Lusitanian = l (Figs 4, 5). It appears from the comparison between subfossil spe- cies and recent species sorted after climatic affinity (Appendix 1) that the subfossil species have their domi- nance in the extreme groups, i.e. Arctic = a; Arctic/ Subarctic = as; Arctic, Subarctic and Boreal = asb and Subarctic/Boreal, while the species with a wide toler- ance – Arctic, Subarctic, Boreal and Lusitanian = asbl – have a higher representation within the recent fauna. Also the middle group, which is represented by faunal element from the Subarctic, Boreal and Lusita- nian, the Boreal and Lusitanian (which is the most numerous group with 140 subfossil species) has a higher representation in the recent fauna. But the group of purely Lusitanian species has a clearly better repre- sentation among the subfossil species, as seen by the percentage figure 6.2% compared to 0.7% for the purely Lusitanian faunal elements among the subfossil and recent faunas respectively. These observations reveal that the Late Quaternary fauna covers a period of 130 000 years with changing climatic conditions both with colder and warmer peri- ods than at present. So considering the totals of subfossil and recent species one has to discuss the difference not only quan- titatively but qualitatively; because only 184 species are shared between the Late Quaternary and the re- cent finds, while 63 species have to be considered as particular ones occurring within the Late Quaternary during the Eemian, the Weichselian or the Holocene, in one, two or in all three groups but not the recent one. Within the Bivalvia, the highest amount of subfossil species (31) found only in the Late Quaternary occur. Such species are also the species which must be fo- cused on in the evaluation of the changing environ- ment through time. Fig. 5. Regional division of the European seas according to Símonarson et al. (1998). GEUS Bulletin no 3.pmd 28-06-2004, 08:4514 15 Molluscan finds within the seven regions during the Holocene The molluscan finds within each region (see Fig. 2) from the Holocene, as appearing mainly from the de- scriptions accompanying the geological map sheets of Denmark, are presented. The Bælt Sea area From the Bælt Sea area the information on the occur- rences of molluscs has been taken from the following map sheets: Madsen (1902) and Jessen (1907 (contri- butions by V.Nordmann), 1935, 1945); V.Milthers (1940) and K. Milthers (1959). Nordmann (1906) has a record of molluscs found in Skælskør Nor (SW Sjælland) and Petersen records from the areas south of Fyn, Storebælt and Lillebælt (1985c, 1989). Subfossil Holocene species in the Bælt Sea area Class Gastropoda Subclass Prosobranchia Order Neotaenioglossa Littorina littorea (Linnaeus 1758) Littorina obtusata (Linnaeus 1758) Littorina saxatilis (Olivi 1792) Littorina tenebrosa (Montagu 1803) Lacuna pallidula (da Costa 1778) Lacuna vincta (Montagu 1803) Hydrobia ulvae (Pennant 1777) Hydrobia ventrosa (Montagu 1803) Onoba semicostata (Montagu 1803) Rissoa albella Lovén 1846 Rissoa inconspicua Alder 1844 Rissoa membranacea (J. Adams 1800) Bittium reticulatum (da Costa 1778) Order Heterogastropoda Triphora adversa (Montagu 1803) Order Neogastropoda Hinia reticulata (Linnaeus 1758) Subclass Heterobranchia Order Heterostropha Omalogyra atomus (Phillippi 1841) Odostomia conoidea Winckworth 1932 Subclass Opisthobranchia Order Anaspidea Retusa obtusa (Montagu 1803) Retusa truncatula (Bruguière 1792) Akera bullata Müller 1776 Subclass Pulmonata Order Basommatophora Lymnaea peregra (Müller 1774) Class Bivalvia Subclass Pteriomorpha Order Mytiloida Mytilus edulis Linnaeus 1758 Modiolula phaseolina (Philippi 1844) Modiolus modiolus (Linnaeus 1758) Musculus discors (Linnaeus 1767) Order Pterioida Ostrea edulis Linnaeus 1758 Subclass Heterodonta Order Veneroida Mysella bidentata (Montagu 1803) Tridonta borealis Schumacher 1817 Parvicardium exiguum (Gmelin 1791) Parvicardium ovale (Sowerby 1840) Parvicardium scabrum (Philippi 1844) Cerastoderma edule (Linnaeus 1758) Spisula subtruncata (da Costa 1778) Angulus tenuis (da Costa 1778) Macoma balthica (Linnaeus 1758) Scrobicularia plana (da Costa 1778) Abra alba (Wood 1802) Arctica islandica (Linnaeus 1767) Paphia aurea (Gmelin 1791) Tapes decussatus (Linnaeus 1758) Venerupis pullastra (Montagu 1803) Order Myoida Mya arenaria Linnaeus 1758 Mya truncata Linnaeus 1758 Corbula gibba (Olivi 1792) Hiatella arctica (Linnaeus 1758) Barnea candida (Linnaeus 1758) Zirfaea crispata (Linnaeus 1758) Total for the Holocene Bælt Sea: 47 (19.0%) GEUS Bulletin no 3.pmd 28-06-2004, 08:4515 16 The Baltic area The Baltic area is here restricted to the area east of Darss and south of Øresund at Saltholm, which must be considered the Baltic sensu stricto when regarding the present distribution of the marine fauna and also taking into consideration the subfossil Holocene mol- luscan fauna, as will be demonstrated by a following comparison with the other areas. The main map sheet published is by V. Milthers from 1908 with contribu- tions by V. Nordmann on the Holocene molluscan fauna. The subfossil Holocene fauna has also been studied later in the western part by Petersen (1994b). In the description accompanying the map sheet Born- holm (Grönwall & Milthers 1916) there is no record of a mollusc fauna. Subfossil Holocene species in the Baltic area Class Gastropoda Subclass Prosobranchia Order Neotaenioglossa Littorina littorea (Linnaeus 1758) Littorina tenebrosa (Montagu 1803) Hydrobia ulvae (Pennant 1777) Hydrobia ventrosa (Montagu 1803) Rissoa albella Lovén 1846 Rissoa inconspicua Alder 1844 Rissoa membranacea (J. Adams 1800) Bittium reticulatum (da Costa 1778) Aporrhais pespelicani (Linnaeus 1758) Order Neogastropoda Hinia reticulata (Linnaeus 1758) Subclass Opisthobranchia Order Anaspidea Retusa truncatula (Bruguière 1792) Subclass Pulmonata Order Basommatophora Lymnaea peregra (Müller 1774) Class Bivalvia Subclass Pteriomorpha Order Mytiloida Mytilus edulis Linnaeus 1758 Subclass Heterodonta Order Veneroida Parvicardium exiguum (Gmelin 1791) Cerastoderma edule (Linnaeus 1758) Cerastoderma glaucum (Poiret 1789) Macoma balthica (Linnaeus 1758) Scrobicularia plana (da Costa 1778) Order Myoida Corbula gibba (Olivi 1792) Total for the Holocene Baltic: 19 (7.7%) The Kattegat area with fjords The Kattegat area sensu lato includes the fjords, i.e. the northern part of the Lillebælt area, Storebælt and Øresund. Therefore the following map sheets are taken within this area: 1. The north-eastern part of Sjælland described by Rørdam (1893), who published a detailed descrip- tion of the Holocene marine deposits from north- east Sjælland already in 1891 and continued with the description of the map sheet København and Roskilde (1899) where the southernmost parts of the Roskilde Fjord and the Øresund are described in great detail for the marine Holocene part. 2. Furthermore, Rørdam & V. Milthers published the description for the geological map sheet of NW Sjælland in 1900 and Nordmann on the molluscs in Sidinge fjord (Westerby 1933). 3. From the north-western part of Fyn and the island of Samsø by Madsen (1897, 1900) and together with Ussing for the north-eastern part of Fyn (Ussing & Madsen 1897). 4. The map sheet of Fredericia (Nordmann 1958) cov- ers the northern part of the Lillebælt and Vejle Fjord on the eastern coast of Jylland. 5. From the islands of Læsø and Anholt in the Kattegat the description was given by Jessen (1897) and Nordmann (1903a). 6. From Hobro by Nordmann (Jessen 1927). 7. From Mariager Fjord by Nordmann (Ødum 1929). 8. The peninsula of Djursland has been mapped dur- ing the last decades, and the description of the Holo- cene marine molluscan fauna is by Petersen (Pedersen & Petersen 1997) and Petersen (1993). Subfossil Holocene species in the Kattegat Class Gastropoda Subclass Prosobranchia Order Archaeogastropoda Theodoxus fluviatilis (Linnaeus 1758) Order Neotaenioglossa Littorina littorea (Linnaeus 1758) Littorina obtusata (Linnaeus 1758) Littorina saxatilis (Olivi 1792) Littorina tenebrosa (Montagu 1803) Lacuna vincta (Montagu 1803) Hydrobia ulvae (Pennant 1777) Hydrobia ventrosa (Montagu 1803) Skeneopsis planorbis (Fabricius 1780) Onoba semicostata (Montagu 1803) Onoba vitrea (Montagu 1803) GEUS Bulletin no 3.pmd 28-06-2004, 08:4516 17 Rissoa albella Lovén 1846 Rissoa inconspicua Alder 1844 Rissoa membranacea (J. Adams 1800) Bittium reticulatum (da Costa 1778) Order Heterogastropoda Triphora adversa (Montagu 1803) Order Neogastropoda Buccinum undatum Linnaeus 1758 Hinia reticulata (Linnaeus 1758) Subclass Heterobranchia Order Heterostropha Omalogyra atomus (Phillippi 1841) Brachystomia eulimoides Hanley 1844 Chrysallida spiralis (Montagu 1803) Subclass Opisthobranchia Order Anaspidea Retusa obtusa (Montagu 1803) Retusa truncatula (Bruguière 1792) Akera bullata Müller 1776 Class Bivalvia Subclass Pteriomorpha Order Mytiloida Mytilus edulis Linnaeus 1758 Musculus discors (Linnaeus 1767) Order Pterioida Heteranomia squamula (Linnaeus 1758) Ostrea edulis Linnaeus 1758 Subclass Heterodonta Order Veneroida Mysella bidentata (Montagu 1803) Acanthocardia echinata (Linnaeus 1758) Parvicardium exiguum (Gmelin 1791) Parvicardium scabrum (Philippi 1844) Cerastoderma edule (Linnaeus 1758) Cerastoderma glaucum (Poiret 1798) Macoma balthica (Linnaeus 1758) Scrobicularia plana (da Costa 1778) Abra alba (Wood 1802) Arctica islandica (Linnaeus 1767) Paphia aurea (Gmelin 1791) Tapes decussatus (Linnaeus 1758) Venerupis pullastra (Montagu 1803) Order Myoida Mya arenaria Linnaeus 1758 Mya truncata Linnaeus 1758 Corbula gibba (Olivi 1792) Hiatella rugosa (Linnaeus 1758) Total for the Holocene Kattegat: 45 (18.2%) The Limfjord area From the Limfjord area (western part), excluding the part which falls within Vendsyssel, only one descrip- tion for a map sheet has been published (Gry 1979). However, the molluscs are recorded in publications by Petersen (1976, 1981, 1985a, 1986a) and in Rasmus- sen & Petersen (1980). Furthermore, V.Nordmann col- lected Holocene marine shells from the western Lim- fjord in 1902–1903 which were further examined by Erna Nordmann and Leifur Símonarson in the sixties as mentioned in Petersen (1976, p. 78). It must be em- phasised that C.G.J. Petersen in 1888 discussed the subfossil fauna also from the Limfjord, which was ear- lier the topic of Collin (1884). Subfossil Holocene species in the Limfjord Class Gastropoda Subclass Prosobranchia Order Archaeogastropoda Patella vulgata Linnaeus 1758 Helcion pellucidum (Linnaeus 1758) Iothia fulva (Müller 1776) Acmaea tessulata (Müller 1776) Acmaea virginea (Müller 1776) Margarites helicinus (Phipps 1774) Gibbula cineraria (Linnaeus 1758) Gibbula tumida (Montagu 1803) Skenea serpuloides (Montagu 1808) Skenea basistriata (Jeffreys 1877) Order Neotaenioglossa Littorina littorea (Linnaeus 1758) Littorina obtusata (Linnaeus 1758) Littorina saxatilis (Olivi 1792) Littorina tenebrosa (Montagu 1803) Lacuna pallidula (da Costa 1778) Lacuna parva (Montagu 1803) Lacuna vincta (Montagu 1803) Hydrobia ulvae (Pennant 1777) Hydrobia ventrosa (Montagu 1803) Skeneopsis planorbis (Fabricius 1780) Alvania lactea (Michaud 1830) Alvania punctura (Montagu 1803) Cingula semistriata (Montagu 1808) Onoba semicostata (Montagu 1803) Onoba proxima (Forbes & Hanley 1850) Onoba vitrea (Montagu 1803) Rissoa albella Lovén 1846 Rissoa inconspicua Alder 1844 Rissoa membranacea (J. Adams 1800) Rissoa parva (da Costa 1779) Rissoa violacea Desmarest 1814 GEUS Bulletin no 3.pmd 28-06-2004, 08:4517 18 Caecum glabrum (Montagu 1803) Bittium reticulatum (da Costa 1778) Turritella communis Risso 1826 Aporrhais pespelicani (Linnaeus 1758) Lunatia alderi (Forbes 1838) Lunatia catena (da Costa 1778) Order Heterogastropoda Triphora adversa (Montagu 1803) Cerithiopsis barleei (Jeffreys 1867) Cerithiopsis tubercularis (Montagu 1803) Epitonium clathrus (Linnaeus 1758) Epitonium turtonis (Turton 1819) Aclis minor (Brown 1827) Vitreolina philippii (Rayneval & Ponzi 1854) Order Neogastropoda Nucella lapillus (Linnaeus 1758) Buccinum undatum Linnaeus 1758 Hinia incrassata (Ström 1768) Hinia pygmaea (Lamarck 1822) Hinia reticulata (Linnaeus 1758) Oenopota turricola (Montagu 1803) Raphitoma purpurea (Montagu 1803) Raphitoma linearis (Montagu 1803) Subclass Heterobranchia Order Heterostropha Omalogyra atomus (Phillippi 1841) Brachystomia eulimoides Hanley 1844 Odostomia scalaris MacGillivray 1843 Chrysallida decussata (Montagu 1803) Chrysallida eximia (Jeffreys 1849) Chrysallida indistincta (Montagu 1808) Chrysallida obtusa (Brown 1827) Chrysallida spiralis (Montagu 1803) Ebala nitidissima (Montagu 1803) Eulimella laevis (Brown 1827) Eulimella scillae (Scacchi 1835) Ondina divisa (J. Adams 1797) Ondina diaphana (Jeffreys 1848) Odostomia acuta Jeffreys 1848 Odostomia conoidea Winckworth 1932 Odostomia turrita Hanley 1844 Odostomia albella Lovén 1846 Odostomia plicata (Montagu 1803) Turbonilla crenata (Brown 1827) Turbonilla delicata (Monterosato 1874) Turbonilla lactea (Linnaeus 1758) Subclass Opisthobranchia Order Bullomorpha Acteon tornatilis (Linnaeus 1758) Cylichna cylindracea (Pennant 1777) Cylichna alba (Brown 1827) Philine aperta (Linnaeus 1767) Philine punctata (Adams 1800) Order Anaspidea Diaphana minuta Brown 1827 Retusa obtusa (Montagu 1803) Retusa truncatula (Bruguière 1792) Retusa umbilicata (Montagu 1803) Akera bullata Müller 1776 Class Bivalvia Subclass Palaeotaxodonta Order Nuculoida Nucula nitidosa Winckworth 1930 Nucula nucleus (Linnaeus 1767) Nuculoma tenuis (Montagu 1808) Subclass Pteriomorpha Order Mytiloida Mytilus edulis Linnaeus 1758 Modiolula phaseolina (Philippi 1844) Modiolus adriaticus (Lamarck 1819) Modiolus modiolus (Linnaeus 1758) Musculus discors (Linnaeus 1767) Modiolaria tumida (Hanley 1843) Order Pterioida Aequipecten opercularis (Linnaeus 1758) Chlamys varia (Linnaeus 1758) Delectopecten vitreus (Gmelin 1791) Palliolum striatum (Müller 1776) Palliolum tigerinum (Müller 1776) Pododesmus patelliformis (Linnaeus 1761) Anomia ephippium Linnaeus 1758 Heteranomia squamula (Linnaeus 1758) Ostrea edulis Linnaeus 1758 Subclass Heterodonta Order Veneroida Lucinoma borealis (Linnaeus 1758) Thyasira flexuosa (Montagu 1803) Mysella bidentata (Montagu 1803) Tellimya ferruginosa (Montagu 1803) Turtonia minuta (Fabricius 1780) Lepton nitidum (Turton 1822) Tridonta borealis Schumacher 1817 Acanthocardia echinata (Linnaeus 1758) Parvicardium exiguum (Gmelin 1791) Parvicardium ovale (Sowerby 1840) Parvicardium scabrum (Philippi 1844) Cerastoderma edule (Linnaeus 1758) Cerastoderma glaucum (Poiret 1789) Mactra stultorum (Linnaeus 1758) Lutraria lutraria (Linnaeus 1758) Spisula elliptica (Brown 1827) Spisula solida (Linnaeus 1758) GEUS Bulletin no 3.pmd 28-06-2004, 08:4518 19 Spisula subtruncata (da Costa 1778) Ensis ensis (Linnaeus 1758) Phaxas pellucidus (Pennant 1777) Angulus tenuis (da Costa 1778) Fabulina fabula (Gmelin 1791) Macoma balthica (Linnaeus 1758) Donax vittatus (da Costa 1778) Gari fervensis (Gmelin 1791) Scrobicularia plana (da Costa 1778) Abra alba (Wood 1802) Abra nitida (Müller 1776) Abra prismatica (Montagu 1803) Arctica islandica (Linnaeus 1767) Chamelea striatula (da Costa 1778) Clausinella fasciata (da Costa 1778) Paphia aurea (Gmelin 1791) Tapes decussatus (Linnaeus 1758) Timoclea ovata (Pennant 1777) Venerupis rhomboides (Pennant 1777) Venerupis pullastra (Montagu 1803) Mysia undata (Pennant 1777) Order Myoida Mya truncata Linnaeus 1758 Corbula gibba (Olivi 1792) Hiatella arctica (Linnaeus 1758) Saxicavella jeffreysi Winckworth 1930 Barnea candida (Linnaeus 1758) Pholas dactylus Linnaeus 1758 Zirfaea crispata (Linnaeus 1758) Subclass Anomalodesmata Order Pholadomyoida Thracia phaseolina (Lamarck 1818) Total for the Holocene Limfjord: 147 (59.5%) The North Sea In the North Sea region the map sheet Blaavands Huk (Fig. 1) forms the southernmost part of what is cov- ered by the present presentation regarding the Holo- cene deposits, and this area was described by Jessen (1925). Nordmann (in Jessen 1925) contributed with the study of the molluscs. 1. In the work by Petersen (1985a) the molluscan fauna in the coastal region – the Aggertange – is recorded. 2. The geological map sheet from Ulfborg was pub- lished by Petersen et al. (1992a), and the molluscan fauna treated by Petersen, but not yet published, is included. 3. In 1994 the Holocene molluscs from the Jydske Rev were studied and reported in a work for the Danish Coastal Authority (Petersen 1994a), and with minor corrections published in Petersen (1998). Subfossil Holocene species in the North Sea Class Gastropoda Subclass Prosobranchia Order Archaeogastropoda Gibbula cineraria (Linnaeus 1758) Theodoxus fluviatilis (Linnaeus 1758) Order Neotaenioglossa Littorina littorea (Linnaeus 1758) Littorina obtusata (Linnaeus 1758) Littorina saxatilis (Olivi 1792) Lacuna pallidula (da Costa 1778) Lacuna parva (Montagu 1803) Lacuna vincta (Montagu 1803) Hydrobia ulvae (Pennant 1777) Hydrobia ventrosa (Montagu 1803) Cingula turgida (Jeffreys 1870) Onoba vitrea (Montagu 1803) Rissoa albella Lovén 1846 Rissoa inconspicua Alder 1844 Rissoa membranacea (J. Adams 1800) Rissoa violacea Desmarest 1814 Caecum glabrum (Montagu 1803) Bittium reticulatum (da Costa 1778) Turritella communis Risso 1826 Aporrhais pespelicani (Linnaeus 1758) Lunatia alderi (Forbes 1838) Lunatia catena (da Costa 1778) Order Heterogastropoda Triphora adversa (Montagu 1803) Epitonium clathrus (Linnaeus 1758) Aclis ascaris (Turton 1819) Aclis minor (Brown 1827) Aclis walleri Jeffreys 1867 Order Neogastropoda Nucella lapillus (Linnaeus 1758) Buccinum undatum Linnaeus 1758 Hinia pygmaea (Lamarck 1822) Hinia reticulata (Linnaeus 1758) Subclass Heterobranchia Order Heterostropha Brachystomia eulimoides Hanley 1844 Chrysallida indistincta (Montagu 1808) Chrysallida spiralis (Montagu 1803) Eulimella laevis (Brown 1827) Ondina diaphana (Jeffreys 1848) Odostomia conoidea Winckworth 1932 GEUS Bulletin no 3.pmd 28-06-2004, 08:4519 20 Odostomia albella Lovén 1846 Turbonilla crenata (Brown 1827) Turbonilla delicata (Monterosato 1874) Turbonilla lactea (Linnaeus 1758) Subclass Opisthobranchia Order Bullomorpha Acteon tornatilis (Linnaeus 1758) Cylichna alba (Brown 1827) Order Anaspidea Retusa obtusa (Montagu 1803) Retusa truncatula (Bruguière 1792) Retusa umbilicata (Montagu 1803) Class Bivalvia Subclass Palaeotaxodonta Order Nuculoida Nucula nitidosa Winckworth 1930 Nucula nucleus (Linnaeus 1767) Nucula sulcata (Bronn 1831) Nuculoma tenuis (Montagu 1808) Subclass Pteriomorpha Order Mytiloida Mytilus edulis Linnaeus 1758 Musculus discors (Linnaeus 1767) Order Pterioida Chlamys varia (Linnaeus 1758) Heteranomia squamula (Linnaeus 1758) Ostrea edulis Linnaeus 1758 Subclass Heterodonta Order Veneroida Thyasira flexuosa (Montagu 1803) Mysella bidentata (Montagu 1803) Tellimya ferruginosa (Montagu 1803) Lepton nitidum (Turton 1822) Acanthocardia echinata (Linnaeus 1758) Parvicardium exiguum (Gmelin 1791) Parvicardium ovale (Sowerby 1840) Parvicardium scabrum (Philippi 1844) Parvicardium minimum (Philippi 1836) Cerastoderma edule (Linnaeus 1758) Mactra stultorum (Linnaeus 1758) Spisula elliptica (Brown 1827) Spisula solida (Linnaeus 1758) Spisula subtruncata (da Costa 1778) Ensis ensis (Linnaeus 1758) Phaxas pellucidus (Pennant 1777) Angulus tenuis (da Costa 1778) Fabulina fabula (Gmelin 1791) Macoma balthica (Linnaeus 1758) Donax vittatus (da Costa 1778) Scrobicularia plana (da Costa 1778) Abra alba (Wood 1802) Abra nitida (Müller 1776) Arctica islandica (Linnaeus 1767) Chamelea striatula (da Costa 1778) Clausinella fasciata (da Costa 1778) Paphia aurea (Gmelin 1791) Tapes decussatus (Linnaeus 1758) Timoclea ovata (Pennant 1777) Venerupis pullastra (Montagu 1803) Dosinia exoleta (Linnaeus 1758) Dosinia lincta (Montagu 1803) Order Myoida Mya truncata Linnaeus 1758 Corbula gibba (Olivi 1792) Hiatella arctica (Linnaeus 1758) Saxicavella jeffreysi Winckworth 1930 Barnea candida (Linnaeus 1758) Zirfaea crispata (Linnaeus 1758) Subclass Anomalodesmata Order Pholadomyoida Cochlodesma praetenue (Pulteney 1799) Thracia phaseolina (Lamarck 1818) Total for the Holocene North Sea: 95 (38.5%) The Vendsyssel area The Vendsyssel area includes the description accom- panying the map sheets over the northern, central and southern parts, all by Jessen (1899, 1905), but with a contribution by V. Nordmann, who wrote the part on the Holocene molluscan fauna in the latter publica- tion. In this description by Nordmann he presents the different faunal communities as discovered in the sub- fossil assemblages. It was Nordmann’s intention to continue the work further west into the western Lim- fjord area, but his first investigations were not used in the systematic geological mapping. They were, how- ever, of great importance for the understanding of the development of the Holocene molluscan fauna (Nord- mann 1910, 1918). In 1928 in connection with the International Con- gress in Copenhagen a final overview by Nordmann of the Quaternary marine deposits in Denmark was given in the Summary of the Geology of Denmark (Madsen et al. 1928). Here Nordmann points to the Dosinia layers first described at the beginning of the century from Vendsyssel (Nordmann 1904), with a record of a fauna not found in the older Tapes beds originally demonstrated by Petersen (1888). GEUS Bulletin no 3.pmd 28-06-2004, 08:4520 21 Later investigations by Lauersen (1937) and Peter- sen (1990,1991a, b, 1992) on the Dosinia beds at Strand- by are also included in the list of Holocene marine molluscs from Vendsyssel. In Just Pedersen’s thesis on Holocene molluscs from 1976 (unpublished), a new fauna element Donax vittatus in the Dosinia beds is recorded from Frede- rikshavn. Subfossil Holocene species in the Vendsyssel Class Gastropoda Subclass Prosobranchia Order Archaeogastropoda Helcion pellucidum (Linnaeus 1758) Acmaea virginea (Müller 1776) Gibbula cineraria (Linnaeus 1758) Gibbula tumida (Montagu 1803) Order Neotaenioglossa Littorina littorea (Linnaeus 1758) Littorina obtusata (Linnaeus 1758) Littorina saxatilis (Olivi 1792) Littorina tenebrosa (Montagu 1803) Lacuna pallidula (da Costa 1778) Lacuna parva (Montagu 1803) Lacuna vincta (Montagu 1803) Hydrobia ulvae (Pennant 1777) Skeneopsis planorbis (Fabricius 1780) Alvania lactea (Michaud 1830) Alvania cimicoides (Forbes 1844) Alvania punctura (Montagu 1803) Cingula semistriata (Montagu 1808) Onoba semicostata (Montagu 1803) Onoba vitrea (Montagu 1803) Rissoa albella Lovén 1846 Rissoa inconspicua Alder 1844 Rissoa membranacea (J. Adams 1800) Rissoa parva (da Costa 1779) Rissoa violacea Desmarest 1814 Caecum glabrum (Montagu 1803) Bittium reticulatum (da Costa 1778) Turritella communis Risso 1826 Aporrhais pespelicani (Linnaeus 1758) Trivia monacha (da Costa 1778) Lunatia alderi (Forbes 1838) Lunatia catena (da Costa 1778) Order Heterogastropoda Triphora adversa (Montagu 1803) Epitonium clathrus (Linnaeus 1758) Epitonium turtonis (Turton 1819) Vitreolina philippii (Rayneval & Ponzi 1854) Order Neogastropoda Nucella lapillus (Linnaeus 1758) Buccinum undatum Linnaeus 1758 Neptunea antiqua (Linnaeus 1758) Hinia incrassata (Ström 1768) Hinia pygmaea (Lamarck 1822) Hinia reticulata (Linnaeus 1758) Cytharella coarctata (Forbes 1840) Oenopota turricola (Montagu 1803) Raphitoma linearis (Montagu 1803) Subclass Heterobranchia Order Heterostropha Omalogyra atomus (Phillippi 1841) Brachystomia eulimoides Hanley 1844 Odostomia scalaris MacGillivray 1843 Chrysallida indistincta (Montagu 1808) Chrysallida obtusa (Brown 1827) Chrysallida spiralis (Montagu 1803) Ebala nitidissima (Montagu 1803) Eulimella laevis (Brown 1827) Odostomia conoidea Winckworth 1932 Odostomia turrita Hanley 1844 Odostomia albella Lovén 1846 Odostomia plicata (Montagu 1803) Turbonilla lactea (Linnaeus 1758) Subclass Opisthobranchia Order Bullomorpha Acteon tornatilis (Linnaeus 1758) Cylichna cylindracea (Pennant 1777) Philine aperta (Linnaeus 1767) Philine punctata (Adams 1800) Order Anaspidea Diaphana minuta Brown 1827 Retusa obtusa (Montagu 1803) Retusa truncatula (Bruguière 1792) Retusa umbilicata (Montagu 1803) Akera bullata Müller 1776 Class Bivalvia Subclass Palaeotaxodonta Order Nuculoida Nucula nitidosa Winckworth 1930 Nucula nucleus (Linnaeus 1767) Subclass Pteriomorpha Order Mytiloida Mytilus edulis Linnaeus 1758 Modiolula phaseolina (Philippi 1844) Modiolus adriaticus (Lamarck 1819) Modiolus modiolus (Linnaeus 1758) Musculus discors (Linnaeus 1767) Modiolaria tumida (Hanley 1843) Order Pterioida Aequipecten opercularis (Linnaeus 1758) GEUS Bulletin no 3.pmd 28-06-2004, 08:4521 22 Chlamys varia (Linnaeus 1758) Pecten maximus (Linnaeus 1758) Pododesmus patelliformis (Linnaeus 1761) Anomia ephippium Linnaeus 1758 Heteranomia squamula (Linnaeus 1758) Ostrea edulis Linnaeus 1758 Subclass Heterodonta Order Veneroida Lucinoma borealis (Linnaeus 1758) Thyasira flexuosa (Montagu 1803) Mysella bidentata (Montagu 1803) Tellimya ferruginosa (Montagu 1803) Turtonia minuta (Fabricius 1780) Lepton nitidum (Turton 1822) Kellia suborbicularis (Montagu 1803) Acanthocardia echinata (Linnaeus 1758) Parvicardium exiguum (Gmelin 1791) Parvicardium ovale (Sowerby 1840) Parvicardium scabrum (Philippi 1844) Cerastoderma edule (Linnaeus 1758) Laevicardium crassum (Gmelin 1791) Mactra stultorum (Linnaeus 1758) Lutraria lutraria (Linnaeus 1758) Spisula elliptica (Brown 1827) Spisula solida (Linnaeus 1758) Spisula subtruncata (da Costa 1778) Ensis ensis (Linnaeus 1758) Phaxas pellucidus (Pennant 1777) Angulus tenuis (da Costa 1778) Fabulina fabula (Gmelin 1791) Macoma balthica (Linnaeus 1758) Macoma calcarea (Gmelin 1791) Donax vittatus (da Costa 1778) Gari depressa (Pennant 1777) Gari fervensis (Gmelin 1791) Scrobicularia plana (da Costa 1778) Abra alba (Wood 1802) Abra nitida (Müller 1776) Abra prismatica (Montagu 1803) Arctica islandica (Linnaeus 1767) Chamelea striatula (da Costa 1778) Clausinella fasciata (da Costa 1778) Paphia aurea (Gmelin 1791) Tapes decussatus (Linnaeus 1758) Timoclea ovata (Pennant 1777) Venerupis rhomboides (Pennant 1777) Venerupis pullastra (Montagu 1803) Dosinia exoleta (Linnaeus 1758) Dosinia lincta (Montagu 1803) Mysia undata (Pennant 1777) Order Myoida Mya arenaria Linnaeus 1758 Mya truncata Linnaeus 1758 Corbula gibba (Olivi 1792) Hiatella arctica (Linnaeus 1758) Hiatella rugosa (Linnaeus 1758) Saxicavella jeffreysi Winckworth 1930 Barnea candida (Linnaeus 1758) Pholas dactylus Linnaeus 1758 Zirfaea crispata (Linnaeus 1758) Subclass Anomalodesmata Order Pholadomyoida Thracia phaseolina (Lamarck 1818) Total for Holocene Vendsyssel: 133 (53.8%) The Skagen Well area The hitherto recorded molluscan assemblages from Danish deposits of Late Quaternary age are littoral to sublittoral – mostly – especially from the Holocene. The new information from the Skagen Well containing deeper-water deposits is presented below. Subfossil Holocene species in the Skagen Well Class Gastropoda Subclass Prosobranchia Order Neotaenioglossa Lacuna pallidula (da Costa 1778) Hydrobia ulvae (Pennant 1777) Barleeia unifasciata (Montagu 1803) Onoba vitrea (Montagu 1803) Rissoa albella Lovén 1846 Rissoa violacea Desmarest 1814 Bittium reticulatum (da Costa 1778) Turritella communis Risso 1826 Aporrhais pespelicani (Linnaeus 1758) Lunatia alderi (Forbes 1838) Lunatia montagui (Forbes 1838) Order Heterogastropoda Epitonium trevelyanum (Johnston 1841) Aclis minor (Brown 1827) Polygireulima sinuosa (Sacco 1836) Vitreolina collensi (Sykes 1903) Vitreolina philippii (Rayneval & Ponzi 1854) Graphis albida (Kanmacher 1798) Melanella lubrica (Monterosato 1891) Melanella alba (da Costa 1778) Hemiaclis ventrosa (Jeffreys MS Fricle 1874) Order Neogastropoda Buccinum undatum Linnaeus 1758 GEUS Bulletin no 3.pmd 28-06-2004, 08:4522 23 Hinia pygmaea (Lamarck 1822) Hinia reticulata (Linnaeus 1758) Oenopota turricola (Montagu 1803) Mangelia brachystoma (Philippi 1844) Subclass Heterobranchia Order Heterostropha Chrysallida decussata (Montagu 1803) Eulimella scillae (Scacchi 1835) Odostomia conoidea Winckworth 1932 Odostomia umbilicaris (Malm 1863) Turbonilla delicata (Monterosato 1874) Turbonilla sinuosa (Jeffreys 1884) Subclass Opisthobranchia Order Bullomorpha Cylichna alba (Brown 1827) Order Anaspidea Retusa truncatula (Bruguière 1792) Retusa umbilicata (Montagu 1803) Class Bivalvia Subclass Palaeotaxodonta Order Nuculoida Nucula nitidosa Winckworth 1930 Nucula nucleus (Linnaeus 1767) Nuculana minuta (Müller 1776) Subclass Pteriomorpha Order Mytiloida Mytilus edulis Linnaeus 1758 Musculus discors (Linnaeus 1767) Order Pterioida Chlamys varia (Linnaeus 1758) Heteranomia squamula (Linnaeus 1758) Ostrea edulis Linnaeus 1758 Subclass Heterodonta Order Veneroida Thyasira flexuosa (Montagu 1803) Mysella bidentata (Montagu 1803) Tellimya ferruginosa (Montagu 1803) Turtonia minuta (Fabricius 1780) Acanthocardia echinata (Linnaeus 1758) Parvicardium minimum (Philippi 1836) Mactra stultorum (Linnaeus 1758) Spisula subtruncata (da Costa 1778) Phaxas pellucidus (Pennant 1777) Angulus tenuis (da Costa 1778) Fabulina fabula (Gmelin 1791) Tellina pygmaea (Lovén 1846) Donax vittatus (da Costa 1778) Gari fervensis (Gmelin 1791) Abra alba (Wood 1802) Abra nitida (Müller 1776) Abra prismatica (Montagu 1803) Arctica islandica (Linnaeus 1767) Chamelea striatula (da Costa 1778) Timoclea ovata (Pennant 1777) Order Myoida Mya arenaria Linnaeus 1758 Corbula gibba (Olivi 1792) Hiatella arctica (Linnaeus 1758) Saxicavella jeffreysi Winckworth 1930 Barnea candida (Linnaeus 1758) Pholas dactylus Linnaeus 1758 Subclass Anomalodesmata Order Pholadomyoida Lyonsia norvegica (Gmelin 1791) Cochlodesma praetenue (Pulteney 1799) Thracia phaseolina (Lamarck 1818) Total for Holocene Skagen Well: 71 (28.7%) GEUS Bulletin no 3.pmd 28-06-2004, 08:4523